math/s_csin_template.c

   1 /* Complex sine function for float types.
   2    Copyright (C) 1997-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <complex.h>
  20 #include <fenv.h>
  21 #include <math.h>
  22 #include <math_private.h>
  23 #include <math-underflow.h>
  24 #include <float.h>
  25
  26 CFLOAT
  27 M_DECL_FUNC (__csin) (CFLOAT x)
  28 {
  29   CFLOAT retval;
  30   int negate = signbit (__real__ x);
  31   int rcls = fpclassify (__real__ x);
  32   int icls = fpclassify (__imag__ x);
  33
  34   __real__ x = M_FABS (__real__ x);
  35
  36   if (__glibc_likely (icls >= FP_ZERO))
  37     {
  38       /* Imaginary part is finite.  */
  39       if (__glibc_likely (rcls >= FP_ZERO))
  40         {
  41           /* Real part is finite.  */
  42           const int t = (int) ((M_MAX_EXP - 1) * M_MLIT (M_LN2));
  43           FLOAT sinix, cosix;
  44
  45           if (__glibc_likely (__real__ x > M_MIN))
  46             {
  47               M_SINCOS (__real__ x, &sinix, &cosix);
  48             }
  49           else
  50             {
  51               sinix = __real__ x;
  52               cosix = 1;
  53             }
  54
  55           if (negate)
  56             sinix = -sinix;
  57
  58           if (M_FABS (__imag__ x) > t)
  59             {
  60               FLOAT exp_t = M_EXP (t);
  61               FLOAT ix = M_FABS (__imag__ x);
  62               if (signbit (__imag__ x))
  63                 cosix = -cosix;
  64               ix -= t;
  65               sinix *= exp_t / 2;
  66               cosix *= exp_t / 2;
  67               if (ix > t)
  68                 {
  69                   ix -= t;
  70                   sinix *= exp_t;
  71                   cosix *= exp_t;
  72                 }
  73               if (ix > t)
  74                 {
  75                   /* Overflow (original imaginary part of x > 3t).  */
  76                   __real__ retval = M_MAX * sinix;
  77                   __imag__ retval = M_MAX * cosix;
  78                 }
  79               else
  80                 {
  81                   FLOAT exp_val = M_EXP (ix);
  82                   __real__ retval = exp_val * sinix;
  83                   __imag__ retval = exp_val * cosix;
  84                 }
  85             }
  86           else
  87             {
  88               __real__ retval = M_COSH (__imag__ x) * sinix;
  89               __imag__ retval = M_SINH (__imag__ x) * cosix;
  90             }
  91
  92           math_check_force_underflow_complex (retval);
  93         }
  94       else
  95         {
  96           if (icls == FP_ZERO)
  97             {
  98               /* Imaginary part is 0.0.  */
  99               __real__ retval = __real__ x - __real__ x;
 100               __imag__ retval = __imag__ x;
 101             }
 102           else
 103             {
 104               __real__ retval = M_NAN;
 105               __imag__ retval = M_NAN;
 106
 107               feraiseexcept (FE_INVALID);
 108             }
 109         }
 110     }
 111   else if (icls == FP_INFINITE)
 112     {
 113       /* Imaginary part is infinite.  */
 114       if (rcls == FP_ZERO)
 115         {
 116           /* Real part is 0.0.  */
 117           __real__ retval = M_COPYSIGN (0, negate ? -1 : 1);
 118           __imag__ retval = __imag__ x;
 119         }
 120       else if (rcls > FP_ZERO)
 121         {
 122           /* Real part is finite.  */
 123           FLOAT sinix, cosix;
 124
 125           if (__glibc_likely (__real__ x > M_MIN))
 126             {
 127               M_SINCOS (__real__ x, &sinix, &cosix);
 128             }
 129           else
 130             {
 131               sinix = __real__ x;
 132               cosix = 1;
 133             }
 134
 135           __real__ retval = M_COPYSIGN (M_HUGE_VAL, sinix);
 136           __imag__ retval = M_COPYSIGN (M_HUGE_VAL, cosix);
 137
 138           if (negate)
 139             __real__ retval = -__real__ retval;
 140           if (signbit (__imag__ x))
 141             __imag__ retval = -__imag__ retval;
 142         }
 143       else
 144         {
 145           __real__ retval = __real__ x - __real__ x;
 146           __imag__ retval = M_HUGE_VAL;
 147         }
 148     }
 149   else
 150     {
 151       if (rcls == FP_ZERO)
 152         __real__ retval = M_COPYSIGN (0, negate ? -1 : 1);
 153       else
 154         __real__ retval = M_NAN;
 155       __imag__ retval = M_NAN;
 156     }
 157
 158   return retval;
 159 }
 160
 161 declare_mgen_alias (__csin, csin)